Assembly for making a polymeric medical device

CROSS-REFERENCE TO RELATED APPLICATIONS

0001This application is a continuation of U.S. application Ser. No. 12/579,359, filed Oct. 14, 2009, now U.S. Pat. No. 8,066,762, which is a divisional of U.S. application Ser. No. 11/157,145, filed on Jun. 20, 2005, now U.S. Pat. No. 7,622,070, both of which applications are incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

0002The invention relates to radially expandable endoprostheses which are adapted to be implanted in a lumen of a tubular organ. An “endoprosthesis”, or stent, corresponds to an artificial implantable medical device that is placed inside the body. A “lumen” refers to a cavity of a tubular organ such as a blood vessel. A stent is an example of these endoprostheses. Stents are generally cylindrically shaped devices which function to hold open and sometimes expand a segment of a blood vessel or other anatomical lumens such as urinary tracts and bile ducts. Stents are often used in the treatment of atherosclerotic stenosis in blood vessels. “Stenosis refers to a narrowing or constriction of the diameter of a bodily passage or orifice. In such treatments, stents reinforce vessels and prevent restenosis following angioplasty in the vascular system. “Restenosis” refers to the reoccurrence of stenosis in a blood vessel or heart valve after it has been treated (as by balloon angioplasty or valvuloplasty) with apparent success.

0003A treatment involving a stent includes both delivery and deployment of the stent. “Delivery” refers to introducing and transporting the stent through a lumen of a tubular organ to a region requiring treatment. “Deployment” corresponds to the expanding of the stent within the lumen at the treatment region. Delivery and deployment of a stent may be accomplished by positioning the stent about one end of a catheter, inserting the end of the catheter through the skin into the lumen, advancing the catheter in the lumen to a desired treatment location, expanding the stent at the treatment location, and then removing the catheter from the lumen. In the case of a balloon expandable stent, the stent is mounted about a balloon disposed on the catheter. Mounting the stent typically involves compressing or crimping the stent onto the balloon. The stent is then expanded by inflating the balloon. The balloon may then be deflated and the catheter withdrawn. In the case of a self-expanding stent, the stent may be secured to the catheter via a retractable sheath or a sock. When the stent is in a desired bodily location, the sheath may be withdrawn allowing the stent to self-expand.

0004Stents have been made of many materials including metals and polymers. Polymer materials include both nonbioerodable and bioerodable plastic materials. In some applications, a polymeric bioerodable stent may be more advantageous than a metal stent due to its biodegradeability and increased flexibility relative to the metal stent. The cylindrical structure of a stent is typically composed of a scaffolding that includes a pattern or network of interconnecting structural elements or struts. The scaffolding can be formed from wires, tubes, or planar films of material rolled into a cylindrical shape. In addition, a medicated stent may be fabricated by coating the surface of either a metallic or polymeric scaffolding with a polymeric carrier. The polymeric carrier can include an active agent or drug. Furthermore, the pattern that makes up the stent allows the stent to be radially expandable and longitudinally flexible. Longitudinal flexibility facilitates delivery of the stent and rigidity is needed to hold open a lumen of a tubular organ. Generally, the pattern should be designed to maintain the longitudinal flexibility and rigidity required of the stent. The stent should also have adequate strength in the circumferential direction.

0005A number of techniques have been suggested for the fabrication of stents from tubes and planar films or sheets. One such technique involves laser cutting or etching a pattern onto a material. Laser cutting may be performed on a planar film of a material which is then rolled into a tube. Alternatively, a desired pattern may be etched directly onto a tube. Other techniques involve cutting a desired pattern into a sheet or a tube via chemical etching or electrical discharge machining Laser cutting of stents has been described in a number of publications including U.S. Pat. No. 5,780,807 to Saunders, U.S. Pat. No. 5,922,005 to Richter and U.S. Pat. No. 5,906,759 to Richter.

0006In a typical method of manufacturing a metal stent with a laser, a mandrel is placed inside the lumen of metal tubing. A “mandrel” refers to a metal bar or rod on which an implantable medical device may be shaped. The mandrel provides structural support to the tubing as it is being cut and shaped. See, e.g., U.S. Pat. No. 5,780,807 to Saunders.

SUMMARY OF THE INVENTION

0007Briefly and in general terms, the present invention is directed to an assembly for making a polymeric implantable medical device from a polymer tube. In aspects of the present invention, an assembly comprises a mandrel made of a first bioabsorbable polymer; and a tube made of a second bioabsorbable polymer, the tube disposed over the mandrel, the mandrel passing through the tube. In other aspects of the present invention assembly comprises a mandrel having an outer surface made of a first bioabsorbable polymer; and a tube made of a second bioabsorbable polymer, the tube removably disposed over the mandrel.

0008The features and advantages of the invention will be more readily understood from the following detailed description which should be read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

0009<figref idref="DRAWINGS">FIG. 1</figref> illustrates a polymeric stent manufacturing device used in one form of a method for manufacturing a polymeric stent pursuant to the present invention.

0010<figref idref="DRAWINGS">FIG. 2</figref> shows an enlarged view of a polymeric stent manufactured by the stent manufacturing device of <figref idref="DRAWINGS">FIG. 1</figref>.

0011<figref idref="DRAWINGS">FIG. 3</figref> is a cross-sectional view of the polymeric stent of <figref idref="DRAWINGS">FIG. 2</figref>.

0012<figref idref="DRAWINGS">FIG. 4</figref> is an enlarged view of a portion of a distal ring of the polymeric stent of <figref idref="DRAWINGS">FIG. 2</figref>.

0013<figref idref="DRAWINGS">FIG. 5</figref> illustrates an alternative embodiment of a polymeric stent manufacturing device used in one form of a method pursuant to the present invention.

0014<figref idref="DRAWINGS">FIG. 6</figref> is an exploded view of the alternative embodiment of the device in <figref idref="DRAWINGS">FIG. 5</figref>.

0015<figref idref="DRAWINGS">FIG. 7A</figref> illustrates an embodiment of a polymeric mandrel of the present invention and used in one form of a method of the present invention.

0016<figref idref="DRAWINGS">FIG. 7B</figref> illustrates an alternative embodiment of a polymeric mandrel of the present invention and used in one form of a method of the present invention.

0017<figref idref="DRAWINGS">FIG. 8</figref> illustrates a second alternative embodiment of a polymeric stent manufacturing device used in one form of a method pursuant to the present invention.

0018<figref idref="DRAWINGS">FIG. 9</figref> shows an enlarged view of a polymeric stent manufactured by the stent manufacturing device of <figref idref="DRAWINGS">FIG. 5</figref>.

0019<figref idref="DRAWINGS">FIG. 10</figref> is a cross-sectional view of the polymeric stent of <figref idref="DRAWINGS">FIG. 9</figref>.

0020<figref idref="DRAWINGS">FIG. 11</figref> is an enlarged view of a portion of a distal ring of the polymeric stent of <figref idref="DRAWINGS">FIG. 9</figref>.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

0021A polymeric stent may be manufactured by a variety of methods. In one method, the polymeric stent may be formed by laser cutting a flat polymeric sheet in the form of rings and links, and then subsequently rolling the pattern into the shape of the cylindrical stent and providing a longitudinal weld to form the stent. In another method, a flat polymeric sheet may be chemically etched and then subsequently rolled and welded to form the polymeric stent. Additionally, a polymeric wire may be coiled to form a polymeric stent. In yet another method, a polymeric stent may be formed from a tube by laser cutting a pattern of cylindrical rings and connecting rings in the tube itself. See, e.g., U.S. Pat. No. 6,585,755 to Jackson et al.

0022In a conventional lasing process of manufacturing a polymeric stent from a tube, a mandrel may not typically be employed. Due to the retentive nature of polymeric materials for foreign particulates, a glass or metal mandrel may contaminate the polymeric stent if a laser beam from the laser strikes it and releases such contaminates. In other words, a glass mandrel may leave glass particulates, and a metal mandrel may leave large amounts of metal oxide contamination melted into the inner surface of the polymer stent, respectively. Such contaminants may cause adverse effects during and/or after the stent is implanted into the lumen of a bodily organ.

0023Non-use of a mandrel in the manufacturing process of a polymeric stent, however, may cause problems aside from contamination through use of glass or metal mandrels. It has been observed that in the manufacture of polymeric stents, damage to the inner surface of the stent can occur. The damage is typically in the form of at least one angled cut, or “nick”, within the inner surface area. The angled cuts are the result of the laser beam reaching the inner surface as the equal-but-opposite outer surface is being lased. The damage caused thereby may cause problems with delivery of the stent and/or adverse body reactions. This problem may be remedied by use of a typical mandrel (which may provide a shielding effect) in the manufacturing process; however, the problems associated with the use of metal or glass mandrels as described previously may result.

0024<figref idref="DRAWINGS">FIG. 1</figref> illustrates an embodiment of a polymeric stent manufacturing device <b>30</b>′ related to the manufacturing process of a polymeric stent. Device <b>30</b>′ for supporting a stent <b>10</b>′ (not shown in <figref idref="DRAWINGS">FIG. 1</figref>) includes a support member <b>32</b>′ and a lock member <b>36</b>′. Support member <b>32</b>′ may connect to a motor <b>38</b>A′ to provide rotational motion about the longitudinal axis of a stent (depicted by arrow <b>40</b>′). Another motor <b>38</b>B′ may also be provided for moving device <b>30</b>′ in a back and forth linear direction along rail <b>42</b>′. Polymeric stent manufacturing device <b>30</b>′ may be in fluid communication with a vacuum device <b>44</b>′ for collecting excess polymeric material. Lock member <b>36</b>′ may be coupled to the vacuum device <b>44</b>′ via a conduit <b>46</b>′. A coupler <b>48</b>′ allows device <b>30</b>′ to rotate with respect to conduit <b>46</b>′ and vacuum <b>44</b>′. In some embodiments, “device” <b>44</b>′ can be a temperature adjuster for adjusting the temperature of the tube <b>8</b> to a temperature other than room temperature before, during and/or after the etching process.

0025In the manufacturing process, a polymeric tube <b>8</b> may be mounted between support member <b>32</b>′ and lock member <b>36</b>′. The wall thickness of the polymeric tube <b>8</b> will typically vary throughout the tube body due to variations in the manufacturing process of polymeric tubes. A coaxial gas jet, rotary collet, tube support and beaming block apparatus of a laser (from hereonout abbreviated as a laser <b>100</b>) may then be used for the etching process to form a polymeric stent <b>10</b>′ from the polymeric tube <b>8</b>. The laser <b>100</b> can include a laser beam <b>102</b>, a focusing lens <b>104</b>, a gas input <b>106</b>, a coaxial gas jet assay <b>108</b> and a gas jet <b>110</b>. A resultant polymeric stent <b>10</b>′ manufactured using device <b>30</b>′ is illustrated in <figref idref="DRAWINGS">FIG. 2</figref>. Polymeric stent <b>10</b>′ includes a plurality of struts <b>12</b>′ linked by connecting elements <b>14</b>′ with gaps <b>16</b>′ positioned in between struts <b>12</b>′ and connecting elements <b>14</b>′. The polymeric stent <b>10</b>′ can include a proximal ring <b>18</b>′, a distal ring <b>20</b>′ and at least one central ring <b>22</b>′.

0026<figref idref="DRAWINGS">FIG. 3</figref> is a cross-section of the polymeric stent <b>10</b>′ of <figref idref="DRAWINGS">FIG. 2</figref>. As shown, the stent <b>10</b>′ includes an inner surface <b>26</b>′ and an outer surface <b>24</b>′. The inner surface <b>26</b>′ of the stent <b>10</b>′ may have at least one “nick” or angled cut <b>28</b> when manufactured using the device <b>30</b>′ as discussed in connection with <figref idref="DRAWINGS">FIG. 1</figref>. In <figref idref="DRAWINGS">FIG. 4</figref>, an enlarged view of a portion of the distal ring <b>20</b>′ is depicted. In this view, at least one angled cut <b>28</b> on the inner surface <b>26</b>′ can be seen more clearly. It should be understood that the angled cuts <b>28</b> may occur throughout the inner surface <b>26</b>′ of the stent <b>10</b>′.

0027The manufacturing process as discussed in connection with <figref idref="DRAWINGS">FIG. 1</figref> may lead to the manifestation of angled cuts <b>28</b>. For example, a shielding effect to the inner surface of a polymeric tube that would otherwise be provided by a mandrel during the manufacturing process of a polymeric stent contributes to the manifestation of angled cuts <b>28</b>. In addition, the inherent varying wall thickness of the polymeric tubes may contribute to the manifestation of angled cuts <b>28</b>. As an illustration, the power of the laser <b>100</b> may be adjusted to etch a first portion of the polymeric tube <b>8</b> with a first thickness. However, this same power may be too strong for the etching of a second portion of polymeric tube <b>8</b> with a second thickness. As a result, although appropriate for the first portion of polymeric tube <b>8</b> with the first thickness, the same power of the laser <b>100</b> for the second portion of the polymer tube <b>8</b> with the second thickness may be too strong and therefore cause the manifestation of angled cuts <b>28</b>. Consequently, the yield of viable polymeric stents using the method and device as discussed above will typically be in the range of 30% to 90%.

0028In <figref idref="DRAWINGS">FIGS. 5 and 6</figref>, an embodiment of a polymeric stent manufacturing device <b>30</b> related to a manufacturing process of the present invention is illustrated. Device <b>30</b> for supporting a stent <b>10</b> (not shown in this figure) can include a support member <b>32</b>, a polymeric mandrel <b>34</b> and a lock member <b>36</b>. A polymeric mandrel is a mandrel made wholly or in part from at least one type of polymer of a combination of polymers, such as in a blended chemically bonded or grafted form. The polymeric mandrel can also be a mandrel that is coated with at least one type of polymer or a combination of polymers. Support member <b>32</b> may connect to a motor <b>38</b>A to provide rotational motion about the longitudinal axis of a stent (depicted by arrow <b>40</b>). Another motor <b>38</b>B may also be provided for moving device <b>30</b> in a back-and-forth linear direction along rail <b>42</b>. The types and specifications of the various motors which can be used in any of the embodiments herein would be apparent to those skilled in the art. The term stent is broadly intended to include self- and balloon-type as well stent-grafts. Polymeric stent manufacturing device <b>30</b> can be in fluid communication with a vacuum device <b>44</b> for collecting excess material that may discharge off of the mandrel <b>34</b> or the stent <b>10</b>. In addition, lock member <b>36</b> is coupled to vacuum device <b>44</b> via a conduit <b>46</b>. A coupler <b>48</b> allows device <b>30</b> to rotate with respect to conduit <b>46</b> and vacuum <b>44</b>. In some embodiments, “device” <b>44</b> can be a temperature adjuster for adjusting the temperature of the tube <b>8</b> to a temperature other than room temperature before, during and/or after the etching process.

0029Support member <b>32</b> includes a flat end <b>50</b> that is coupled to a first end <b>52</b> of mandrel <b>34</b>. In accordance to one embodiment, mandrel <b>34</b> can be permanently affixed to support member <b>32</b>. Alternatively, support member <b>32</b> can include a bore <b>54</b> for receiving first end <b>52</b> of mandrel <b>34</b>. First end <b>52</b> of mandrel <b>34</b> can be threaded to screw into bore <b>54</b>. Alternatively, a non-threaded first end <b>52</b> of mandrel <b>34</b> can be press-fitted or friction-fitted within bore <b>54</b>. Bore <b>54</b> should be deep enough so as to allow mandrel <b>34</b> to securely mate with support member <b>32</b>. The depth of bore <b>54</b> can be over-extended so as to allow a significant length of mandrel <b>34</b> to penetrate the bore. This would allow the length of mandrel <b>34</b> to be adjusted to accommodate stents of various sizes.

0030Lock member <b>36</b> can include a flat end <b>56</b> that can be permanently affixed to a second end <b>58</b> of mandrel <b>34</b> if end <b>52</b> of mandrel <b>34</b> is disengagable from support member <b>32</b>. A bore <b>54</b> extends along lock member <b>36</b> for allowing mandrel <b>34</b> to be in fluid communication with vacuum device <b>44</b>. In accordance with another embodiment, mandrel <b>34</b> can have a threaded second end <b>58</b> for screwing into bore <b>54</b>. A non-threaded second end <b>58</b> and bore <b>54</b> combination can also be employed such that second end <b>58</b> of mandrel <b>34</b> is press-fitted or friction-fitted within bore <b>54</b>. Lock member <b>36</b> can be incrementally moved closer to support member <b>32</b>. Accordingly, stents of any length can be securely pinched between flat ends <b>50</b> and <b>56</b> of the support and lock members <b>32</b> and <b>36</b>. A stent need not, however, be pinched between ends <b>50</b> and <b>56</b>; a stent can be simply crimped tightly on mandrel <b>34</b>.

0031An embodiment of a portion of polymeric mandrel <b>34</b> is illustrated in <figref idref="DRAWINGS">FIG. 7A</figref> and includes a hollow tubular body having a mandrel bore <b>60</b> extending through the body of mandrel <b>34</b>. In addition, mandrel <b>34</b> may have pores <b>62</b> on its surface that are in communication with mandrel bore <b>60</b>. In other words, pores <b>62</b> penetrate all the way through the body of mandrel <b>34</b>. Mandrel bore <b>60</b> and pores <b>62</b> can be of any suitable size and the number of pores <b>62</b> can be selected for effectively allowing excess material to be vacuumed off of the stent and mandrel <b>34</b>. However, the pores <b>62</b> should not cause manufacturing defects. In some embodiments, the vacuum device <b>34</b> should be able to apply positive pressure so as to blow out air or a gas (such as an inert gas, for example, argon) in or out from the mandrel <b>34</b>. The blowing or vacuuming can be conducted during or after the laser etching. In an alternative embodiment, the mandrel <b>34</b> may be solid (see <figref idref="DRAWINGS">FIG. 7B</figref>).

0032Polymeric mandrel <b>34</b> can be made from or coated with a biostable polymer or a bioerodable, biodegradable or bioabsorbable polymer. Bioerodable, biodegradable or bioabsorbable are intended to be used interchangeably unless otherwise indicated. In some embodiments, the polymer is the same as a polymer used to make the implantable medical device or stent <b>10</b>. In some embodiments, the polymer can be different, so long as the polymer is biocompatible. If a combination of polymers is used from the device or mandrel <b>34</b>, at least one of the polymers can be the same.

0033Representative examples of biocompatible polymers that can be used for mandrel <b>34</b> include, but are not limited to, fluorinated polymers or copolymers such as poly(vinylidene fluoride), poly(vinylidene fluoride-co-hexafluoro propene), poly(tetrafluoroethylene), and expanded poly(tetrafluoroethylene); poly(sulfone); poly(Nvinyl pyrrolidone); poly(aminocarbonates); poly(iminocarbonates); poly(anhydride-coimides), poly(hydroxyvalerate); poly(L-lactic acid); poly(L-lactide); poly(caprolactones); poly(lactide-co-glycolide); poly(hydroxybutyrates); poly(hydroxybutyrate-co-valerate); poly(dioxanones); poly(orthoesters); poly(anhydrides); poly(glycolic acid); poly(glycolide); poly(D,L-lactic acid); poly(D,L-lactide); poly(glycolic acid-co-trimethylene carbonate); poly(phosphoesters); poly(phosphoester urethane); poly(trimethylene carbonate); poly(iminocarbonate); poly(ethylene); and any derivatives, analogs, homologues, congeners, salts, copolymers and combinations thereof.

0034In some embodiments, the polymers include, but are not limited to, poly(propylene) co-poly(ether-esters) such as, for example, poly(dioxanone) and poly(ethylene oxide)/poly(lactic acid); poly(anhydrides), poly(alkylene oxalates); poly(phosphazenes); poly(urethanes); silicones; poly(esters; poly(olefins); copolymers of poly(isobutylene); copolymers of ethylene-alphaolefin; vinyl halide polymers and copolymers such as poly(vinyl chloride); poly(vinyl ethers) such as, for example, poly(vinyl methyl ether); poly(vinylidene halides) such as, for example, poly(vinylidene chloride); poly(acrylonitrile); poly(vinyl ketones); poly(vinyl aromatics) such as poly(styrene); poly(vinyl esters) such as poly(vinyl acetate); copolymers of vinyl monomers and olefins such as poly(ethylene-co-vinyl alcohol) (EVAL), copolymers of acrylonitrile-styrene, ABS resins, and copolymers of ethylene-vinyl acetate; and any derivatives, analogs, homologues, congeners, salts, copolymers and combinations thereof.

0035In some embodiments, the polymers include, but are not limited to, poly(amides) such as Nylon 66 and poly(caprolactam); alkyd resins; poly(carbonates); poly(oxymethylenes); poly(imides); poly(ester amides); poly(ethers) including poly(alkylene glycols) such as, for example, poly(ethylene glycol) and poly(propylene glycol); epoxy resins; polyurethanes; rayon; rayon-triacetate; biomolecules such as, for example, fibrin, fibrinogen, starch, poly(amino acids); peptides, proteins, gelatin, chondroitin sulfate, dermatan sulfate (a copolymer of D-glucuronic acid or L-iduronic acid and N-acetyl-D-galactosamine), collagen, hyaluronic acid, and glycosaminoglycans; other polysaccharides such as, for example, poly(N-acetylglucosamine), chitin, chitosan, cellulose, cellulose acetate, cellulose butyrate, cellulose acetate butyrate, cellophane, cellulose nitrate, cellulose propionate, cellulose ethers, and carboxymethylcellulose; and any derivatives, analogs, homologues, congeners, salts, copolymers and combinations thereof.

0036In some embodiments, at least one of polymers can be a poly(ester amide), a poly(lactide) or a poly(lactide-co-glycolide) copolymer; and any derivatives, analogs, homologues, congeners, salts, copolymers and combinations thereof.

0037In some embodiments, the polymers can be biodegradable, bioerodable and/or bioabsorbable. Examples of biodegradable polymers include, but are not limited to, polymers having repeating units such as, for example, an a-hydroxycarboxylic acid, a cyclic diester of an a-hydroxycarboxylic acid, a dioxanone, a lactone, a cyclic carbonate, a cyclic oxalate, an epoxide, a glycol, an anhydride, a lactic acid, a glycolic acid, a lactide, a glycolide, an ethylene oxide, an ethylene glycol, and any derivatives, analogs, homologues, congeners, salts, copolymers and combinations thereof.

0038In some embodiments, the biodegradable polymers include, but are not limited to, polyesters, poly(ester amides); poly(hydroxyalkanoates) (PHA), amino acids; PEG and/or alcohol groups; polycaprolactones, poly(D-lactide), poly(L-lactide), poly(D,L-lactide), poly(meso-lactide), poly(L-lactide-co-meso-lactide), poly(D-lactide-comeso-lactide), poly(D,L-lactide-co-meso-lactide), poly(D,L-lactide-co-PEG) block copolymers, poly(D,L-lactide-co-trimethylene carbonate), polyglycolides, poly(lactide-coglycolide), polydioxanones, polyorthoesters, polyanhydrides, poly(glycolic acid-cotrimethylene carbonate), polyphosphoesters, polyphosphoester urethanes, poly(amino acids), polycyanoacrylates, poly(trimethylene carbonate), poly(imino carbonate), polycarbonates, polyurethanes, copoly(ether-esters) (e.g. PEO/PLA), polyalkylene oxalates, polyphosphazenes, PHA-PEG, and any derivatives, analogs, homologues, salts, copolymers and combinations thereof.

0039In other embodiments, the polymers can be poly(glycerol sebacate); tyrosine-derived polycarbonates containing desaminotyrosyl-tyrosine alkyl esters such as, for example, desaminotyrosyl-tyro sine ethyl ester (poly(DTE carbonate)); and any derivatives, analogs, homologues, salts, copolymers and combinations thereof.

0040In some embodiments, the polymers are selected such that they specifically exclude any one or any combination of any of the polymers taught herein.

0041<figref idref="DRAWINGS">FIG. 8</figref> illustrates a view of polymeric stent mandrel device <b>30</b> according to another embodiment of the invention. Support member <b>32</b> and lock member <b>36</b> include conical end portions <b>56</b>A and <b>56</b>B, instead of flat ends, for penetrating into ends of stent <b>10</b>. The end portions <b>56</b>A and <b>56</b>B can taper inwardly at an angle 0₁of about 15° to about 75°, more narrowly from about 30° to about 60°. By way of example, angle 0, can be about 45°. The outer surface of mandrel <b>34</b> will typically be smaller than the inner surface of stent <b>10</b>, as positioned on fixture <b>30</b>, so as to prevent the outer surface of mandrel <b>34</b> from making contact with the inner surface of stent <b>10</b>.

0042In the manufacturing process using device <b>30</b>, a polymeric tube <b>8</b> may be placed on the polymeric mandrel <b>34</b> between support member <b>32</b> and lock member <b>36</b>. The polymeric tube <b>8</b> may typically be between twelve to two-hundred millimeters long depending on its intended therapeutic application. Additionally, the inner and outer surfaces of the polymeric tube <b>8</b> may vary in accordance with the intended therapeutic application and in correspondence with the outer surface of the mandrel <b>34</b>. In some embodiments, the OD of the polymeric tube <b>8</b> may approximately be equivalent to the ID of the mandrel <b>34</b>. In other embodiments, the OD of the polymeric tube <b>8</b> may be smaller than the ID of the mandrel <b>34</b>. For example, for a polymeric tube <b>8</b> of size 0.084″OD and 0.070″ID, a corresponding polymer mandrel in the range of 0.025″ OD to 0.035″ OD may be used. Generally, mandrels may range in size from 0.010″ OD to 0.050″ OD, typically supplied in the sizes 0.014″ OD or 0.035″ OD.

0043A laser <b>100</b> may then be used for the etching process to form a polymeric stent <b>10</b> from polymeric tube <b>8</b>. The laser <b>100</b> may be used in a range of fifty milliwatts to one watt, depending on the environmental conditions surrounding the laser. In contrast to the method employing device <b>30</b>′, the method employing device <b>30</b> with polymeric mandrel <b>34</b> reduces the need to tailor the power from the laser <b>100</b> to the wall thickness of the polymer tube <b>8</b>, thus reducing the time it takes to cut the stent <b>10</b>. A typical lasing process takes approximately two minutes to twelve minutes, more particularly approximately six minutes, pursuant to a method of this invention.

0044In <figref idref="DRAWINGS">FIG. 9</figref>, a polymeric stent <b>10</b> manufactured in accordance with device <b>30</b> is illustrated. As discussed previously, the polymeric stent <b>10</b> can include a plurality of struts <b>12</b> linked by connecting elements <b>14</b>, with gaps <b>16</b> positioned between the struts and the connecting elements. The polymeric stent <b>10</b> can also include a proximal ring <b>18</b>, a distal ring <b>20</b> and at least one central ring <b>22</b>. Generally, the polymeric stent <b>10</b> is a bioerodable, biodegradable or bioabsorbable implantable medical device that is intended to remain in the body until its intended function is achieved.

0045In <figref idref="DRAWINGS">FIGS. 10 and 11</figref>, cross-sectional and enlarged views of the polymer stent of <figref idref="DRAWINGS">FIG. 9</figref> are illustrated, respectively. Generally absent from the inner surface <b>26</b> is at least one angled cut <b>28</b>. This is substantially due to the mandrel <b>34</b>, which provides a shielding effect to the inner surface <b>26</b> when the equal-but-opposite outer surface <b>24</b> is being lased during the manufacturing process. Moreover, because the mandrel <b>34</b> is comprised of a biocompatible polymer, the problems of undesirable residual contaminants left by typical glass or metal mandrels, for example, are substantially reduced or completely eliminated. Finally, using the method related to device <b>30</b>, slight wall thickness variations of the polymeric tube <b>8</b> can be tolerated to a greater extent due to the shielding effect of the polymeric mandrel <b>34</b> as discussed previously. Overall, a higher yield of usable commercially polymeric stents may be produced using the method employing device <b>30</b> with polymeric mandrel <b>34</b>. It is anticipated that the yield of polymeric stents using the method and device as just described will approach 100%.

0046The polymeric stent <b>10</b> described in <figref idref="DRAWINGS">FIGS. 9</figref>, <b>10</b> and <b>11</b> may be coated with one or more therapeutic agents, including an anti-proliferative, anti-inflammatory or immune modulating, anti-migratory, anti-thrombotic or other pro-healing agent or a combination thereof. The anti-proliferative agent can be a natural proteineous agent such as a cytotoxin or a synthetic molecule or other substances such as actinomycin D, or derivatives and analogs thereof (manufactured by Sigma-Aldrich 1001 West Saint Paul Avenue, Milwaukee, Wis. 53233; or COSMEGEN available from Merck) (synonyms of actinomycin D include dactinomycin, actinomycin IV, actinomycin 11, actinomycin X1, and actinomycin C1), all taxoids such as taxols, docetaxel, and paclitaxel, paclitaxel derivatives, all olimus drugs such as macrolide antibiotics, rapamycin, everolimus, structural derivatives and functional analogues of rapamycin, structural derivatives and functional analogues of everolimus, FKBP-12 mediated mTOR inhibitors, biolimus, perfenidone, prodrugs thereof, co-drugs thereof, and combinations thereof. Representative rapamycin derivatives include 40-0-(3-hydroxy)propyl-rapamycin, 40-0-[2-(2-hydroxy)ethoxy]ethyl-rapamycin, or 40-0-tetrazole-rapamycin, 40-epi-(N1-tetrazolyl)-rapamycin (ABT-578 manufactured by Abbot Laboratories, Abbot Park, Ill.), prodrugs thereof, co-drugs thereof, and combinations thereof.

0047The anti-inflammatory agent can be a steroidal anti-inflammatory agent, a nonsteroidal anti-inflammatory agent, or a combination thereof. In some embodiments, anti-inflammatory drugs include, but are not limited to, alclofenac, alclometasone dipropionate, algestone acetonide, alpha amylase, amcinafal, amcinafide, amfenac sodium, amiprilose hydrochloride, anakinra, anirolac, anitrazafen, apazone, balsalazide disodium, bendazac, benoxaprofen, benzydamine hydrochloride, bromelains, broperamole, budesonide, carprofen, cicloprofen, cintazone, cliprofen, clobetasol propionate, clobetasone butyrate, clopirac, cloticasone propionate, cormethasone acetate, cortodoxone, deflazacort, desonide, desoximetasone, dexamethasone dipropionate, diclofenac potassium, diclofenac sodium, diflorasone diacetate, diflumidone sodium, diflunisal, difluprednate, diftalone, dimethyl sulfoxide, drocinonide, endrysone, enlimomab, enolicam sodium, epirizole, etodolac, etofenamate, felbinac, fenamole, fenbufen, fenclofenac, fenclorac, fendosal, fenpipalone, fentiazac, flazalone, fluazacort, flufenamic acid, flumizole, flunisolide acetate, flunixin, flunixin meglumine, fluocortin butyl, fluorometholone acetate, fluquazone, flurbiprofen, fluretofen, fluticasone propionate, furaprofen, furobufen, halcinonide, halobetasol propionate, halopredone acetate, ibufenac, ibuprofen, ibuprofen aluminum, ibuprofen piconol, ilonidap, indomethacin, indomethacin sodium, indoprofen, indoxole, intrazole, isoflupredone acetate, isoxepac, isoxicam, ketoprofen, lofemizole hydrochloride, lomoxicam, loteprednol etabonate, meclofenamate sodium, meclofenamic acid, meclorisone dibutyrate, mefenamic acid, mesalamine, meseclazone, methylprednisolone suleptanate, momiflumate, nabumetone, naproxen, naproxen sodium, naproxol, nimazone, olsalazine sodium, orgotein, orpanoxin, oxaprozin, oxyphenbutazone, paranyline hydrochloride, pentosan polysulfate sodium, phenbutazone sodium glycerate, pirfenidone, piroxicam, piroxicam cinnamate, piroxicam olamine, pirprofen, prednazate, prifelone, prodolic acid, proquazone, proxazole, proxazole citrate, rimexolone, romazarit, salcolex, salnacedin, salsalate, sanguinarium chloride, seclazone, sermetacin, sudoxicam, sulindac, suprofen, talmetacin, talniflumate, talosalate, tebufelone, tenidap, tenidap sodium, tenoxicam, tesicam, tesimide, tetrydamine, tiopinac, tixocortol pivalate, tolmetin, tolmetin sodium, triclonide, triflumidate, zidometacin, zomepirac sodium, aspirin (acetylsalicylic acid), salicylic acid, corticosteroids, glucocorticoids, tacrolimus, pimecorlimus, prodrugs thereof, co-drugs thereof, and combinations thereof.

0048These agents can also have anti-proliferative and/or anti-inflammmatory properties or can have other properties such as antineoplastic, antiplatelet, anticoagulant, anti-fibrin, antithrombonic, antimitotic, antibiotic, antiallergic, antioxidant as well as cystostatic agents. Examples of suitable therapeutic and prophylactic agents include synthetic inorganic and organic compounds, proteins and peptides, polysaccharides and other sugars, lipids, and DNA and RNA nucleic acid sequences having therapeutic, prophylactic or diagnostic activities. Nucleic acid sequences include genes, antisense molecules which bind to complementary DNA to inhibit transcription, and ribozymes. Some other examples of other bioactive agents include antibodies, receptor ligands, enzymes, adhesion peptides, blood clotting factors, inhibitors or clot dissolving agents such as streptokinase and tissue plasminogen activator, antigens for immunization, hormones and growth factors, oligonucleotides such as antisense oligonucleotides and ribozymes and retroviral vectors for use in gene therapy. Examples of antineoplastics and/or antimitotics include methotrexate, azathioprine, vincristine, vinblastine, fluorouracil, doxorubicin hydrochloride (e.g. Adriamycin® from Pharmacia &amp; Upjohn, Peapack N.J.), and mitomycin (e.g. Mutamycin® from Bristol-Myers Squibb Co., Stamford, Conn.). Examples of such antiplatelets, anticoagulants, antifibrin, and antithrombins include sodium heparin, low molecular weight heparins, heparinoids, hirudin, argatroban, forskolin, vapiprost, prostacyclin and prostacyclin analogues, dextran, D-phe-pro-arg-chloromethylketone (synthetic antithrombin), dipyridamole, glycoprotein IIb/IIIa platelet membrane receptor antagonist antibody, recombinant hirudin, thrombin inhibitors such as Angiomax a (Biogen, Inc., Cambridge, Mass.), calcium channel blockers (such as nifedipine), colchicine, fibroblast growth factor (FGF) antagonists, fish oil (omega 3-fatty acid), histamine antagonists, lovastatin (an inhibitor of HMG-CoA reductase, a cholesterol lowering drug, brand name Mevacor® from Merck &amp; Co., Inc., Whitehouse Station, N.J.), monoclonal antibodies (such as those specific for Platelet-Derived Growth Factor (PDGF) receptors), nitroprusside, phosphodiasterase inhibitors, prostaglandin inhibitors, suramin, serotonin blockers, steroids, thioprotease inhibitors, triazolopyrimidine (a PDGF antagonist), nitric oxide or nitric oxide donors, super oxide dismutases, super oxide dismutase mimetic, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl(4-amino-TEMPO), estradiol, anticancer agents, dietary supplements such as various vitamins, and a combination thereof. Examples of such cytostatic substance include angiopeptin, angiotensin converting enzyme inhibitors such as captopril (e.g. Capoten® and Capozide® from Bristol-Myers Squibb Co., Stamford, Conn.), cilazapril or lisinopril (e.g. Prinivil® and Prinzidee from Merck &amp; Co., Inc., Whitehouse Station, N.J.). An example of an antiallergic agent is permirolast potassium. Other therapeutic substances or agents which may be appropriate include alpha-interferon, and genetically engineered epithelial cells. The foregoing substances are listed by way of example and are not meant to be limiting. Other active agents which are currently available or that may be developed in the future are equally applicable.

0049The coating method may be applied by a variety of methods, such as those disclosed in U.S. Pat. No. 6,818,063 to Kerrigan and U.S. Pat. No. 6,695,920 to Pacetti et al. In addition, the therapeutic drug may be incorporated within the polymeric tube <b>8</b> thereof, such as disclosed in U.S. Pat. No. 5,605,696 to Eury et al. Also, the polymeric tube <b>8</b> may include at least two layers of polymers with different chemical characteristics for purposes of, for example, adjusting the flexibility characteristic of the polymeric stent <b>10</b>.

0050From the foregoing detailed description, it will be evident that there are a number of changes, adaptations and modifications of the present invention which come within the province of those skilled in the art. The scope of the invention includes any combination of the elements from the different species or embodiments disclosed herein, as well as subassemblies, assemblies, and methods thereof. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof.